This is a "showy" taijutsu unique to members of the Akimichi clan. After growing in size with the Multi-Size Technique, the Akimichi tucks themselves into a ball and rolls towards a target. Due to their increased weight and the force of their rotation, most obstacles are pulverised upon contact. Users can take advantage of the surrounding environment to launch themselves into the air, increasing the damage when they fall back to the ground. The speed at which they spin has the added benefit of rendering most attacks ineffective against them. But the ball's speed also makes it difficult to turn, forcing users to stop spinning entirely if they want to make significant changes in direction and thus leaving them vulnerable while they do.
How the Human Bullet Tank is used depends on what form the Akimichi's Multi-Size Technique takes. In Part I, when Chōji Akimichi's Multi-Size Technique makes him very round, he retracts his arms, legs, and head into his body so that they don't get in the way while he rolls; because his head is submerged in his bulk, this also makes him immune to external sounds. In Part II, when Chōji's Multi-Size Technique simply makes him large, he folds his legs to his chest and locks his arms around them.
- The full name of this technique is Leaf-Style Taijutsu: Human Bullet Tank (木ノ葉流体術・肉弾戦車, Konoha-Ryū Taijutsu: Nikudan Sensha, Literally meaning: Tree Leaf-Style Body Technique: Human Bullet Tank).
- In the anime, Nagare modelled his Assimilation: Rock Tank after this technique.
- Neji uses a similar technique in Rock Lee's Springtime of Youth Full Power Ninja Chronicles.